Migrating from npm-check

npm-check reports unused dependencies and out-of-date packages, with an interactive updater. rev-dep replaces its unused-dependency analysis and adds checks npm-check doesn't have.

Why migrate

• npm-check is effectively unmaintained (last release 2021). rev-dep is actively developed.
• Speed. rev-dep is Go-based and runs in a single parallel pass - faster on large repos.
• More than unused deps. rev-dep also detects missing dependencies, dev-deps in production, unused exports, orphan files, and architecture rules.

What carries over, what changes

• Covered well: unused dependencies.
• Out of scope - version updates. npm-check's main extra feature is checking for outdated packages and updating them interactively (-u). rev-dep does not manage versions; keep npm outdated or npm-check-updates for that.
• Bonus: rev-dep adds missing-dependency detection, which npm-check does not focus on.

Feature mapping

npm-check	rev-dep
unused dependencies	unusedNodeModulesDetection
-i, --ignore <glob>	excludeModules
-p, --production (skip devDependencies)	enable checks on production entry points; see dev-deps in production
-u / -y (update outdated packages)	- (out of scope; use npm outdated / npm-check-updates)
-	missingNodeModulesDetection

Translating your usage

npm-check
npm-check --ignore "@types/*"

become a rev-dep.config.jsonc:

{
  "rules": [
    {
      "path": ".",
      "unusedNodeModulesDetection": {
        "enabled": true,
        "excludeModules": ["@types/*"]
      },
      "missingNodeModulesDetection": {
        "enabled": true
      }
    }
  ]
}

Tooling-only packages that aren't imported (CLIs, plugins) can be pointed to with pkgJsonFieldsWithBinaries / filesWithBinaries / filesWithModules rather than excluded - see unused node modules.

Running it

# npm-check
npx npm-check

# rev-dep
rev-dep config run

Next steps

• Missing or unused dependency false positives - especially important in monorepos.
• Monorepo integration guide.